A move for Miller remains an option but Keane is doubtful of luring him to Portman Road.
Keane said: "People think I'm doom and gloom but you look at Cardiff last night and we are a world away from that.
"We are miles away from the likes of Cardiff and QPR and people need to realise that. I appreciate my glass is always half empty but that is the reality.
"We are asking young lads to fill in and I am trying to get attacking players in.
"Ishmael Miller will have plenty of options. We are in the market and if you think we are the only club in for a player like him then you are mad.
"He is a good player and good players are always in my thoughts. I don't think we'd be the first option for players from Premier League clubs in the midlands or the north west.
"We have trouble attracting players down here as they don't often want to move away so we may have to look at younger players."